Two tools were needed: a small paintbrush to apply the glue and a screwdriver to put in four screws to retain the varroa floor.
It couldn't have been easier. I think (but not sure) that it would be possible to put in the sides upside down - but you would have to be pretty careless. I can easily be that dumb, but not on this occasion.
The sides fix together with interlocking mortice and tenon joints.
The top and bottom edges of the short sides are re-inforced with hard plastic edges. Easy to slide on.
Verdict: this is so easy, even a klutz like me can do it.